Implemented Call Adapter

[farmery]

Introduced CallAdapters, a feature that allows you to adapt the return type of a network call from one type to another.
For example:
Future<User> → Future<Result<User>>.

A CallAdapter takes the original return type R and transforms it into a new type T. This is particularly useful when working with response wrappers like Either, Result, or ApiResponse.

Sample Code:

class MyCallAdapter<T> extends CallAdapter<Future<T>, Future<Result<T>>> {
  @override
  Future<Result<T>> adapt(Future<T> Function() call) async {
    try {
      final response = await call();
      return Result<T>.ok(response);
    } catch (e) {
      return Result.err(e.toString());
    }
  }
}

@RestApi(callAdapter: MyCallAdapter)
abstract class RestClient {
  factory RestClient(Dio dio, {String? baseUrl}) = _RestClient;

  @GET('/')
  Future<Result<User>> getUser();
}

Generated Code Snippet:

  @override
  Future<Result<User>> getUser() {
    return MyCallAdapter<User>().adapt(
      () => _getUser(),
    );
  }

where the private method "_getUser()" is the method that makes the Api request